This invention relates to power converter configuration, control, and construction.
Power converters generally include power transfer components (e.g., transformers and switches) and control circuitry which governs the operation of the power transfer components to achieve desired operating characteristics. For example, in some zero current switching (ZCS) converters of the kind sold by Vicor Corporation, Andover, Mass. (see also U.S. Pat. Nos. 4,415,959, 4,441,146, and 4,675,797, incorporated by reference), the power transfer components are discrete components mounted on a printed circuit board.
Referring to FIG. 1, in a simple version of a ZCS converter, a main power transformer 10 has primary and secondary windings 12, 14 which define primary and secondary electrical sides 16, 18 of the converter. Power conversion occurs by quantized transfer of energy from the primary side to the secondary side during a succession of energy transfer cycles. Each energy transfer cycle begins and ends with the closing and subsequent opening of a switch 20 at times when the current through the switch is essentially zero.
A control circuit 22 governs the opening and closing of switch 20 so that the energy transfer cycles occur with a frequency that is varied to cause the converter to supply the output power at a desired voltage. A voltage sensor 24 detects Vout and information about Vout (i.e. control information) is fed back to a portion of the control circuit which turns the primary side switch on and off.
It is often important (e.g., for safety reasons) that the primary and secondary sides of the converter be isolated from one another. As a result, the transfer of control information from the secondary to primary sides is usually done via an isolation device (e.g., a transformer in which two windings are coupled by a permeable core, an opto-coupler, or a discrete light emitting device located adjacent to a discrete light detecting device) which is included in the control circuitry.
During construction of the converter, the control circuitry typically is formed by mounting discrete electronic components on the same circuit board that bears the power conversion parts, or on separate daughter boards which form an assembly to be mounted on the main power conversion board (see U.S. patent application Ser. No. 07/947,937, Providing Electrical Components for Circuit Assembly, filed Sep. 21, 1992, incorporated by reference).
Powercube Corporation and General Electric Corporation have offered modular building blocks (e.g., AC rectifier blocks, PWM conversion blocks, control assembly blocks, output rectifier blocks) from which a complete switching power supply could be assembled, by connecting blocks together by means of wires, electrical connectors or traces on a circuit board.